Multipoint electrostatic measurement for lightning prediction

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K13970
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 25030:Disaster prevention engineering-related
• Research Institution: Ashikaga University
• Principal Investigator: Yamashita Kozo 足利大学, 工学部, 准教授 (20609911)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 雷雲 / 雷 / 静電界 / フィールドミル / センサーネットワーク

Outline of Final Research Achievements

In this study, we had developed a methodology for lightning prediction based on quantitative estimation of a macroscopic charge inside a thundercloud (cloud charge). We had newly designed electric field mills and deployed 12 sensors in Tochigi prefecture to measure horizontal electrostatic distribution by a small thundercloud which was isolated spatially (isolated thundercloud). By assuming a simple charge model inside the isolated thundercloud, we obtained the first result to estimate a temporal variation of a cloud charge with 1 second resolution. Development platform for short-term prediction of lightning occurrence had been developed by monitoring the growth or decline of a cloud charge. Initial results indicate the distinctive change of a cloud charge before lightning discharge, which would be effective for a short-term prediction of lightning discharges. Presently, the number of observed isolated thunderclouds is a few and further observation is necessary.

Free Research Field

大気電気学

Academic Significance and Societal Importance of the Research Achievements

本研究の最終目的は、着雷点に甚大な経済的、人的被害をもたらす落雷の発生予測である。本申請課題では、雷放電に電荷を供給する雲内電荷の定量評価を目的とし、地上静電界の多点計測網を構築した。初期結果として孤立雲内の電荷量の定量推定に成功し、発雷予測法の開発基盤を確立した。発雷予測は、雷害対策の新領域を切り開く点において社会的意義がある。また、地上静電界計測のみに基づいた雲内電荷の定量推定事例は国内外でも先行報告が見当たらず、新規性の面より学術的意義も高いと考えられる。